add forEach to Null and Nullable

Author: tsnobip

src/Core__Null.mjs

@@ -39,6 +39,13 @@ function getExn(value) {
       };
 }
 
+function forEach(value, f) {
+  if (value !== null) {
+    return Curry._1(f, value);
+  }
+  
+}
+
 function map(value, f) {
   if (value !== null) {
     return Curry._1(f, value);
@@ -74,6 +81,7 @@ export {
   getOr ,
   getWithDefault ,
   getExn ,
+  forEach ,
   map ,
   mapOr ,
   mapWithDefault ,

src/Core__Null.res

@@ -34,6 +34,12 @@ let getExn: t<'a> => 'a = value =>
 
 external getUnsafe: t<'a> => 'a = "%identity"
 
+let forEach = (value, f) =>
+  switch value->toOption {
+  | Some(x) => f(x)
+  | None => ()
+  }
+
 let map = (value, f) =>
   switch value->toOption {
   | Some(x) => make(f(x))

src/Core__Null.resi

@@ -128,6 +128,19 @@ Null.getUnsafe(null) // Raises an error
 */
 external getUnsafe: t<'a> => 'a = "%identity"
 
+/**
+`forEach(value, f)` call `f` on `value`. if `value` is not `null`, then if calls
+`f`, otherwise returns `unit`.
+
+## Examples
+
+```rescript
+Null.forEach(Null.make("thing"), x => Console.log(x)) // logs "thing"
+Null.forEach(null, x => Console.log(x)) // returns ()
+```
+*/
+let forEach: (t<'a>, 'a => unit) => unit
+
 /**
 `map(value, f)` returns `f(value)` if `value` is not `null`, otherwise returns
 `value` unchanged.

src/Core__Nullable.mjs

@@ -38,6 +38,13 @@ function getExn(value) {
       };
 }
 
+function forEach(value, f) {
+  if (!(value == null)) {
+    return Curry._1(f, value);
+  }
+  
+}
+
 function map(value, f) {
   if (value == null) {
     return value;
@@ -73,6 +80,7 @@ export {
   getOr ,
   getWithDefault ,
   getExn ,
+  forEach ,
   map ,
   mapOr ,
   mapWithDefault ,

src/Core__Nullable.res

@@ -34,6 +34,12 @@ let getExn: t<'a> => 'a = value =>
 
 external getUnsafe: t<'a> => 'a = "%identity"
 
+let forEach = (value, f) =>
+  switch value->toOption {
+  | Some(x) => f(x)
+  | None => ()
+  }
+
 let map = (value, f) =>
   switch value->toOption {
   | Some(x) => make(f(x))

src/Core__Nullable.resi

@@ -138,6 +138,20 @@ Nullable.getUnsafe(Nullable.null) // Raises an error
 */
 external getUnsafe: t<'a> => 'a = "%identity"
 
+/**
+`forEach(value, f)` call `f` on `value`. if `value` is not `null` or `undefined`, 
+then if calls `f`, otherwise returns `unit`.
+
+## Examples
+
+```rescript
+Nullable.forEach(Nullable.make("thing"), x => Console.log(x)) // logs "thing"
+Nullable.forEach(Nullable.null, x => Console.log(x)) // returns ()
+Nullable.forEach(undefined, x => Console.log(x)) // returns ()
+```
+*/
+let forEach: (t<'a>, 'a => unit) => unit
+
 /**
 `map(value, f)` returns `f(value)` if `value` is not `null` or `undefined`,
 otherwise returns `value` unchanged.